Synthesis and characterization of six-coordinate "3 + 2" mixed-ligand oxorhenium complexes with the o-diphenylphosphinophenolato ligand and tridentate coligands of different N and S donor atom combinations

A series of octahedral six-coordinate oxorhenium(V) mixed ligand complexes containing the common ReO(L)]2+ fragment (L = o-OC6H4P(C6H5)2] have been synthesized and characterized. Hence, it was shown that the ReO(L)]2+ moiety can accommodate a variety of tridentate ligands containing a central amine group amenable to deprotonation and different combinations of lateral groups, such as ethylamine, substituted ethylamine, ethylthiol, and ethylthioether arms. In particular, by reaction of equimolar amounts of the pertinent HLn ligands with the (n-C4H9)4N]ReOCl3(L)] precursor in refluxing acetonitrile/methanol or dichloromethane/methanol mixtures, the following series of ReO(Ln)(L)]+/0 oxorhenium(V) complexes has been generated: ReON(CH2CH2NH2)2]o-OC6H4P(C6H5)2]]Cl (1); ReOC2H5)2NCH2CH2NCH2CH2S]o-OC6H4P5)2]] (2); ReO(CH2)4NCH2CH2NCH2CH2S]o-OC6H4P(C6H4P(C6H5)2]] (3); and ReOC2H5SCH2CH2NCH2CH2S]o-OC6H4P(C6H5)2]] (4). The complexes are closed-shell 18-electron oxorhenium species, which adopt octahedral geometries both in solution and in the solid state, as established by conventional physicochemical techniques including multinuclear NMR and single-crystal X-ray diffraction analyses.